Ferritic Stainless Steels

Ferritic stainless steels are stainless alloys or Iron – Chromium alloys with Chromium content between 10.5 to 30%. These steels are straight chromium steels containing little or no nickel. The absence of nickel provides a relatively stable cost base for this material compared to austenitic stainless steels. Ferritic stainless steel has properties similar to mild steel but with the better corrosion resistance. The most common of these steels are 12% and 17% chromium containing steels, with 12% used mostly in structural applications and 17% in housewares, laundry applications and sugar industry. Ferritic grades are used extensively in automotive requirements.

The Characteristics of the ferritic grades are:

• Good corrosion resistance, but generally not as good as 304/316 Austenitic
• Good ductility
• Fully magnetic
• Immune from chloride stress corrosion cracking
• Not suitable for use in low temperature applications
• Can’t be further hardened by heat treatment and only slightly further cold worked
• Stable ferrite structure

Grade and Typical

409 – Heat resistant steel, easily formed and welded. Mainly used for automotive exhausts or welded applications where superior performance to galvanised steel is required.

446 – Used for severe heat resistant applications up to 1200°C. In recuperators, highly resistant to sulphidation and oil ash corrosion.

1.4003 – Good corrosion resistance and readily weldable it provides a cost effective choice for many structural applications where mild or low alloyed steels require regular repair or replacement.